Searching within a specific folder

I’m trying to use find/replace within a folder, using the Find in Project feature. I’ve tried various combinations to specify the folder, eg:
/folder/
/sitename/folder/
C:/wamp64/www/sitename/folder/
file:///C:/wamp64/www/sitename/folder/
I’ve also tried with backward slashes and with asterisks at the beginning and end of the path etc…

Does anyone know how to specify the ‘File/directory pattern’ - for folder names? (Specifying file names works with asterisks.) I would be grateful for any suggestions.